Fluid-pressure brake.



No. 827,880. PATENTED AUG. 7, 1908." A. PARKER-SMITH.

FLUID PRESSURE BRAKE.

APPLICATION FILED DEO.1.1905.

FIG1. E

Wibneooeo 4 aumwmboz To all whom it may concern:

- UNITED STATES PATENT oFrroE.

1 AUGUSTUS PARKER-SMITH, or NEW YORK, N. Y..

. FLum-PRessURE eRA E.

Be it known that I, AUGUSTUS PARKER- SMITH, a citizen of""the United States of. America, and a resident of the borough of Manhattan, city, county, and State of New York, ave invented certain new and useful Improvements in Fluid-Pressure Brakes, of which the following is a specification.

My invention relates to fluid-pressure brake systems, and isdesigned to economize the consum ti on of compressed a irin the wellknown airrake s stems in use on railroad and trolley cars.

which the second cylinder comes into action and produces'a greatly-increased brake-pressure without much additional consumption ofair.

My invention is designed to perfect the action of one form' of such two-cylinder systems in which the operation of the piston in the second cylinder is dependent upon the attain ment of a predetermined pressure in the main cylinder. v

The best form of apparatus at present known to me embodying my invention is illustrated in the accompanying sheet of drawings, in which Figure 1 is a plan view of the two cylinders and their connections. Fig. 2 is a detail in section of my improved arrangement of valves connecting the two cylinders. Fig. 3 is a similar view of a modified form of valve;

Throughout the drawings like referencefigures indicate like parts.

1 represents a portion of the usual system of levers and rods composing the brake rig-' .ging.

2 1s the main cylinder, whose piston 3 is connected to the brake-leversin the usual '4 is a su plemental lever pivoted at 5- to the car-b0 y, connected by rod 6 to iston 3 and by pivot 4 to push-rod 7 which atter telescopes into the hollow piston-rod 8 of piston 9 in the-second cylinder 10.

11 represents any suitable means, such as a friction-clutch, for connecting the piston ofthe second cylinder to the push-rod 7, and thereby to thebrake-levers, when said piston begins to move on its outward stroke.

12 is a pipe'connecting the main cylinder with the second cylinder, and 13 represents diagrammatically in Fig. lthe mechanism Specification of Letters Patent. I Application filed December 1, 1905. Serial No. 289.909.

t has beenheretofore proposed to employ two cylinders in such sys-' tems, the main cylinder serving to take up the slack and the brake-shoe clearance, after brake-shoe clearance.

Patented Aug. 7,1 see.

for controlling the flow of fluid-from one cyl- Y inder to the other through pipe 12. This controlling means consists of a valve 14 ,-openin from the main cylinder to the second cylinder, controlled by piston 14", which is set by means of spring 15 to move and open valve 14 at a predetermined pressure of such fluid-say twenty pounds to the square inch.

(See Fig. 2.) r The unobstructed return-flow when brakes are released is permitted by check-valve 16, located in a by-pass connec tion 17 around said valve 14. The usual auxiliary reservoir is shown at 18, connected to triple valve'19 by'pipe 2.0.

In Fig. 3 the admission-valve 14 is shown located in the return checkva lve 16, the assumption being in each case that the full-line arrows show the direction of fiowof-the air when the brakes 'are being applied, while the dotted-line arrows show the direction of flow whenthe air is escaping from the second cylinder. v

The 0 eration of my invention is as fol lows: en the triple valve 19 is actuated to admit air to main cylinder 2, piston 3 is forced out and the brakes applied in the and the pressure applied to p1s'ton'9 is conveyed to. the lever 4 and by it transmitted with double force to the "brake-rigging. When the brakes are released and pressure oes down in cylinder 2, the air flowsfreely ack through check-valve 16 from cylinder 10 to cylinder 2 and thence to the triplevalve exhaust-port in the usual way. In the modification shown in Fig. 3 the same action takes place, except that .valve14 performs the function of valve 14 and 16 the function of valve 16. u

The advantages of my invention comprise the perfect and simple control of the exhaust which it provides. Heretofore it has been pro osed to employ a spring-governed valve 1n t is combination; but such valve has also ,operated anexhaust-Opening from the sec- 0nd cylinder to the atmos here. Hence when the spring-valve close accidentally during the application of the brakes, as from a reduction of pressure in the main cylinder,

. due'to the flow of air into the second cylinder,

or from leakage in any form,.the exhaust from the second cylinder would be opened and the braking lower of the same lost. This also produce a variable and jerky action of the brakes. My invention avoids this difficulty. When the valve 14 closes, it

merely holds the air in cylinder 10 untilthe main cylinder is exhausted to a lower pres-' sure in the process of releasing the brakes.

Then the check-valve 16 opens and the-air fiows out freely.

It is' evident, of course, that various changes could be made inthe details of con-'- struction illustratedwithout departing'from ond cylinder mi lit-be controlled directly by v the exhaust of t e triple valve 19; but these and similar modifications I should still considerwithin the scope of my invention.

Havingtherefore described my invention,

. I claim 1. In a fluidressure brake system, the

combination wit the brake-levers of armain pressure-cylinder and piston connected to said levers, of a second cylinder and piston supplied with fluid under pressure from the firstcylinder, means for connecting the piston of the second cylinder to the brake-levers when said piston moves on its outstroke, a

valve controlling the flow of air from the. main cylinderto the second cylinder which valve isset to openat a predetermined pressure and a check-valve controlling the re-' tu'rn flow of fluid fromthe second cylinder to the maincylinder.

combination wit the brake-levers of a main pressure-cylinder and piston connected to saidlevers, of a second cylinder and piston 2. -In a fluid-pressure brake system, the

supplied with fluid under pressure from the first cylinder, means 'for connecting the pi ston of the second cyli der. to the brake-levers .when said piston moves on its outstroke, a valve controllingithe flow of air from the main cylinder to the second cylinder whlch valve is set to open at a predetermined pressure, and a check-valve controllin the rei turn flow of'fiuid from thesecond cy inder to,

the'main cylinder, said check-valve being located in a by-pass around saidfirst-mentionedvalve.

3. In a fiuidressure brake system, the

combination wit the brake-levers of a main pressure-cylinder and. iston connected to saidlevers, of a secon "cylinder and piston first cylinder, means for connectin the piston of the second cylinder to the bra e-levers when'said piston moves on its outstroke, a

valve controlling the' flow of air from the main cylinder to the second cylinder which valve is set to open at'a predetermined pressure, and means other than said valve for ex-':

hausting the fluid from said second cylinder. Signed-at New York, N. Y., this28th day of November, 1905.

supplied with fluidunder pressure from the AUGUSTUS PARKERfSMITH. v

Witnesses: v

W. H. PUMPHREY, M. G. CRAWFORD. I 

